Two-thirds of Americans believe we use just 10 percent of our brain. Why that's wrong
It's a myth that we use only 10% of our brains. However, you're not alone in buying into this. A survey done about 10 years ago found that almost two-thirds of Americans shared this misconception. This mistaken belief has been around for more than a century, and I even saw one place where it was misattributed to Albert Einstein to explain the differences in people’s intelligence!
The brain is the most important organ in our bodies. It's the body’s overall control center, directs our actions and behaviors, allows us to feel and to think, and defines us as individuals.
Although it represents only about 2% of our total body weight, it uses up to 25% of our blood flow, 25% of our oxygen utilization and up to 25% of our blood glucose (the major energy source for cells).
What is the brain made of?
The 100 billion nerve cells in our brains provide 2.5 million gigabytes of memory capacity — similar to that of up to 600,000 laptop computers. So, it's natural to wonder whether were using all of these neurons. The evidence that we are is overwhelming. For example:
Functional MRI brain scans (which track the blood supply/neuron activity in the brain) "light up" essentially all over the brain. We even use most areas of our brain while we rest/sleep.
Certain tasks/functions are located in different parts of the brain. For example, Wernicke’s area is where language in processed. And extensive mapping of the brain’s function has yet to identify any "unused" areas.
Direct (via fine electrical probes inserted into a brain) and indirect (for example, from electric encephalograms/EEGs) measurements of the electrical/chemical signals being transmitted through axons (the parts of neurons that carry electric impulses allowing them to communicate with each other) have not identified any unused parts of the brain.
Significant strokes and/or other injuries affecting any area of the brain typically compromise some brain function. If only 10% of the brain was being used, these medical conditions would have only a small likelihood of causing problems, as damage to unused brain areas would not cause loss of function.
Unused brain cells would atrophy/deteriorate, but autopsies of people who died while still having healthy, fully functioning brains do not show areas of deteriorated brain cells.
Why do intelligences differ?
And why are we able to continue to learn (the brain does not seem to "fill up")? This is not well understood, but it's likely that, at least in part, this is because the brain’s function depends on the amount/complexity of connections between the brain’s billions of neurons, and not just the number of neurons. It's known that the brain is constantly making new connections and modifying existing connections, and this is thought to be an integral part of the learning process, and a vital part of creating new memory.
Factors that lead to better brain function
Sleep also seems to be a very important part of creating new memory, although specific details of this are not well understood.
Overall, people who get restful, sufficient and regular sleep, have a healthy diet, do regular physical exercise and have an overall healthy lifestyle have better brain function. So yes, you can improve your brain function to some extent by doing the same things that are good for your heart and for your overall health in general. And yes, "exercising" your brain — for example, by regularly reading, doing things that challenge your brain like working, studying, interacting with others or even regularly doing brain teasers, crosswords, sudokus, etc. — can also help maximize brain function and slow the loss of function that occurs with aging.
Jeff Hersh, Ph.D., M.D., can be reached atDrHersh@juno.com.
This article originally appeared on MetroWest Daily News: Brain function: what we know about it, facts and myths
